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well all i can say is try it for yourself.
When i first read about flat foot shifting, i assumed you didnt need to use the clutch, so i went out and tried it, and i tried to flat foot shift about 3 times, after the first failed attempt i thought perhaps i wasnt at the right revs or something, so i tried again, but even with a strong effort, it wouldn't even come out of gear, never mind go in the next gear.

Try it again using the clutch, and you can just tell it works good.

I think my misunderstanding came from thinking the mk3 focus RS has flat foot shifting, with no clutch needed from 1st to 2nd gear, but wether thats right or not, it certainly doesn't apply to the fiesta.
The only gearboxes i know where you don't need the clutch are the sequential ones that they used to use in something like the Escort Cosworth Rally cars, i saw a video of a bloke who put one in a road car and i believe changing up you don't need the clutch but changing down you did use it, but if you got it wrong it was a very expensive mistake!
 

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2005 mk6 Fiesta ST
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The only gearboxes i know where you don't need the clutch are the sequential ones that they used to use in something like the Escort Cosworth Rally cars
and even then, you lift off the throttle slightly to change, because as someone said above the gear lever doesn't move if it's under hard acceleration load.
 

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Also these gearboxes tend to have straight cut gears (very noisy) and more modern versions have ECU controlling throttle for rev matching up and down and obviously from there you are moving into DSG type with dual clutches, pre engagement of next gear and so on.
I can't see the STs flat shift being of any benefit unless you are running a quarter mile and every 100th Matters, but snatching at cogs like this on super sticky drag racing tarmac won't do the cogs any favours.
 

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If anyone wants to see an excellent video of a sequential box in action in an Escort Cossie road car go onto youtube and type in Bulldozer Escort Cosworth (Davide Cironi - 13 minutes long). It is a great video but the car is no longer as it had a fuel leak and went up in flames 😰
 

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I've tried it a few times and it feels so wrong to me as coming from decades of diesel ownership when 4K rpm is when I'd change up.
But isn't this flat shifting lark simply because of the electronic rev limiter?
So you floor the accelerator pedal and keep it all the way down, then when you hit the rev limiter press the clutch and change gear. The engine revs being prevented from going up further when the clutch is pressed as you are already on the limiter. Without a limiter the revs would go through the roof and the engine goes bang.
If you try this before you've got to the red line then the engine revs fly up.
Or am I missing something ?
 

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Tesla Model 3 Performance MY2021
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I've tried it a few times and it feels so wrong to me as coming from decades of diesel ownership when 4K rpm is when I'd change up.
But isn't this flat shifting lark simply because of the electronic rev limiter?
So you floor the accelerator peddle and keep it all the way down, then when you hit the rev limiter press the clutch and change gear. The engine revs being prevented from going up further when the clutch is pressed as you are already on the limiter. Without a limiter the revs would go through the roof and the engine goes bang.
If you try this before you've got to the red line then the engine revs fly up.
Or am I missing something ?
It stops the revs climbing. So if you shift at lets say 6500rpm and redline is 6750rpm it would keep the revs at 6500rpm IF I have understood it properly. I never used it properly as mine would just blow the tires or wheelhop when shifting with throttle pinned or close to it. You had to add some slippage.
 

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I use the same phylosophy as quoted in Bladerunner for flatshifting: The clutch that slips twice as much, lives half as long.
 
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